Browsing by Author "Yakandawala, K."

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    Crotalaria Retusa L. as a Potential Potted Dwarf Ornamental Plant
    (Uva Wellassa University of Sri Lanka, 2019) Suharshana, E.V.G.A.; Yakandawala, K.; Dewagedara, D.M.A.E.I.; Abenayake, N.R.
    Exotic plants are popular in the ornamental plant industry in Sri Lanka due to their attractiveness. However, maintenance cost of these plants are high due to higher water and nutrient requirements. In Sri Lanka though we have a rich flora, native plants are yet to be introduced to the ornamental plant industry that creates advantages than exotics. Crotalaria retusa, a native annual herb which bears striking yellow flowers that attracts butterflies in large numbers was identified as a potential plant to develop as an ornamental potted plant. Hence, the present study is an attempt to develop C. retusa as a potted plant. Seedlings were raised in black polythene bags in a rain shelter and Paclobutrazol (PBZ) was applied twice as a soil drench with 0.5, 1, 2, 4 and 8 mg per 100 ml concentrations at two weeks interval. Distilled water was used as the control and the pots were arranged in completely randomized design with 15 replicates. Plant height was measured and numbers of leaves were counted in one day interval up to three months in 5 plants per treatment. Leaf colour was measured by using RHS colour chart. Dry weight of shoot, root and leaf of each treatment was measured separately after 12 weeks and the data were analysed by using ANOVA technique. Concentration of 4 mg per 100 ml PBZ exhibited the significantly lowest dry weight and plant height (p<0.05) among the treatments. PBZ inhibits sterol and depress the gibberellin biosynthesis which led to the reduction of intermodal distance resulting dwarf plants. However, the concentrations beyond 4 mg per 100 ml, the plant height was not significantly (p<0.05) reduced irrespective of the concentration. Increasing PBZ levels progressively increased green colour of the leaves and reduced the size of the flowers. Hence, based on the present study, 4mg per 100ml PBZ could be recommended to produce dwarf potted plants of C. retusa for ornamental plant industry.
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    Morphological Characterization and Distribution of Lagenandra praetermissa de Wit & Nicolson
    (Uva Wellassa University of Sri Lanka, 2019-02) Madola, G.K.I.S.; Yakandawala, K.; Yakandawala, D.M.D.; Karunaratne, S.B.
    Lagenandra praetermissa is an aquatic endemic species distributed throughout the Wet and Intermediate zones along the rivers, streams and marshy habitats. According to National Red List 2012 the plant is listed under the “Least Concern” category. The recent field observations indicated a reduction in subpopulations and variations in vegetative morphology. Hence the present study was focused on distribution and morphological diversity of L. praetermissa which would contribute to its conservation. Field collections were made covering Wet, Dry and the Intermediate zones of the country. At least three plants were studied in detail from each population for coding morphological characters. Twenty-three qualitative and quantitative vegetative characters of individuals from 34 different subpopulations were coded into a data matrix and a morphometric analysis was carried out using the PAST software. Distribution of the subpopulations were recorded using GPS locations. Further, the soil pH and threats were also recorded for each location. Although L. praetermissa was recorded as occurring in the Kandy and Kalutara districts during the revision of the family in 1986, according to the present study they were also recorded from Badulla, Kegalle, Kurunegala, Matara, Rathnapura and Monaragala districts which extends its distribution to the dry zone. Even they exhibit a wider distribution, most of these subpopulations occur outside protected areas in polluted disturbed streams and river banks. The soil pH ranged from 4.7-6.3 which is acidic indicating the polluted nature of the habitats. The cluster analysis identified two phonetic groups, separating at a 32 distance units, while these two groups further divided into subclusters. The petiole length and the leaf laminar length were the most contributing characters. The identification of two different phenetic groups of L. praetermissa indicates its morphological diversity which needs to be further studied using molecular data to identify whether these belong to distinct groups.